As President Barack Obama's campaign intensifies criticism of Romney's background, influential Republicans -- right-leaning leaders in business and the media -- charge that Romney's message on the economy and other issues is short on detail and muddled at best.

In an editorial Thursday, The Wall Street Journal said the Romney campaign is "slowly squandering an historic opportunity."

"The Romney campaign thinks it can play it safe and coast to the White House by saying the economy stinks and it's Mr. Obama's fault," the newspaper said. "We're on its email list and the main daily message from the campaign is that 'Obama isn't working.' Thanks, guys, but Americans already know that. What they want to hear from the challenger is some understanding of why the president's policies aren't working and how Mr. Romney's policies will do better."

The harsh critique comes as Romney nears the end of a weeklong vacation at his New Hampshire lakeside home, where he has been almost totally out of the public eye, except for a brief Fourth of July appearance. Polls show Obama slightly leading Romney nationally and in several states that are critical in the hunt to reach the 270 electoral votes needed to win the Nov. 6 election.

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Romney has consistently criticized Obama's handling of the economy, health care, domestic spending and foreign policy, but he has offered few specific prescriptions for what he would do differently. The strategy is reflective of a campaign that hopes to make the election a referendum on Obama -- in particular his handling of the economy -- as economic indicators suggest the pace of the nation's recovery is slowing.

The federal government is set to release a June jobs report on Friday that could have major political ramifications with the election four months away. Regardless of the numbers, conservatives say Romney still needs to better explain his plans.

"Adopting a prevent defense when it's only the second quarter and you're not even ahead is dubious enough as a strategy," William Kristol, editor of the conservative Weekly Standard, wrote Thursday.

The Romney campaign says the former Massachusetts governor has been laser-focused on the economy since he launched his campaign a year ago. And they suggest their critics are misguided.

"I think they have to recognize that we're in a campaign mode where simple, tough, declarative sentences are required, that this is not a campaign to be won on nuance but to be won on making sharp distinctions with the failure of the Obama administration economically, the loss of jobs and the pain that Americans across the country are feeling," former New Hampshire Gov. John H. Sununu, a key Romney surrogate, said on CNN.

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Informal campaign adviser Charlie Black noted that Romney has a 59-point economic plan on his website.

But conservative critics include media mogul Rupert Murdoch, who took to Twitter recently and charged that Obama's Chicago-based team "will be hard to beat unless he drops old friends from team and hires some real pros. Doubtful."

Murdoch, the CEO of News Corp., which owns The Wall Street Journal and Fox News, has also jabbed Romney for playing it safe.

Some of Romney's longtime political advisers go back to his days as Massachusetts governor.

"Governor Romney respects the team that he has and he has full confidence in them," said spokeswoman Gail Gitcho.

The criticism has intensified in the days since the Romney campaign offered seemingly contradictory messages on the Supreme Court's health care ruling. The court ruled that the so-called individual mandate in Obama's signature law is constitutional, in part, because of the federal government's taxing authority.

Republicans seized on the explanation and accused Obama of raising taxes. But that raised questions about Romney's health care overhaul in Massachusetts, which also forces people to purchase health insurance.

A day after a Romney senior adviser declared that the mandate was not a tax, Romney went on TV to say it was.

The president, meanwhile, has launched a two-day bus tour of northern Ohio and western Pennsylvania, where he told supporters Thursday that Romney would pursue economic policies that favor the wealthy at the expense of the middle class. And Obama's top political adviser, David Axelrod, cited an Associated Press investigation of Romney's personal offshore investments.

"Why would you transfer your Bermuda business . to your wife the day before you became governor? Why did you not want that on your disclosure form?" Axelrod told ABC News, accusing Romney of being the most secretive candidate since President Richard Nixon.

But there is little doubt that the direction of the economy on Election Day will be critical.

The June jobs report arrives amid a number of mixed signals on the economy. U.S. manufacturing shrank in June for the first time in nearly three years, according to a report this week. Private payroll provider ADP reported Thursday that U.S. businesses added 176,000 jobs last month, better than the revised total of 136,000 jobs it reported for May. But shoppers pulled back on spending in June, leading to sluggish retail sales during the month.

Another bad jobs report could undermine Obama's argument that the economy has shown signs of improvement.